
<!DOCTYPE html>
<html>

	<head>
		<meta charset="utf-8" />
</head>
	<style>

		#container_pubu {
			box-shadow: inset 0 1px 0 #444, 0 -1px 0 #000;
			height: 140px;
			left: 50%;
			margin: -70px 0 0 -60px;
			position: absolute;
			top: 50%;
			width: 120px;
		}

		canvas {
			display: block;
			margin: 0 auto;
		}
	</style>

	<body>
		<div id="container_pubu">
			<canvas id="waterfall"></canvas>
		</div>

	</body>

</html>
<script>
	var waterfallCanvas = function(c, cw, ch) {

		var _this = this;
		this.c = c;
		this.ctx = c.getContext('2d');
		this.cw = cw;
		this.ch = ch;

		this.particles = [];
		this.particleRate = 6;
		this.gravity = .15;

		this.init = function() {
			this.loop();
		};

		this.reset = function() {
			this.ctx.clearRect(0, 0, this.cw, this.ch);
			this.particles = [];
		};

		this.rand = function(rMi, rMa) {
			return ~~((Math.random() * (rMa - rMi + 1)) + rMi);
		};

		this.Particle = function() {
			var newWidth = _this.rand(1, 20);
			var newHeight = _this.rand(1, 45);
			this.x = _this.rand(10 + (newWidth / 2), _this.cw - 10 - (newWidth / 2));
			this.y = -newHeight;
			this.vx = 0;
			this.vy = 0;
			this.width = newWidth;
			this.height = newHeight;
			this.hue = _this.rand(200, 220);
			this.saturation = _this.rand(30, 60);
			this.lightness = _this.rand(30, 60);
		};

		this.Particle.prototype.update = function(i) {
			this.vx += this.vx;
			this.vy += _this.gravity;
			this.x += this.vx;
			this.y += this.vy;
		};

		this.Particle.prototype.render = function() {
			_this.ctx.strokeStyle = 'hsla(' + this.hue + ', ' + this.saturation + '%, ' + this.lightness + '%, .05)';
			_this.ctx.beginPath();
			_this.ctx.moveTo(this.x, this.y);
			_this.ctx.lineTo(this.x, this.y + this.height);
			_this.ctx.lineWidth = this.width / 2;
			_this.ctx.lineCap = 'round';
			_this.ctx.stroke();
		};

		this.Particle.prototype.renderBubble = function() {
			_this.ctx.fillStyle = 'hsla(' + this.hue + ', 40%, 40%, 1)';
			_this.ctx.fillStyle = 'hsla(' + this.hue + ', ' + this.saturation + '%, ' + this.lightness + '%, .3)';
			_this.ctx.beginPath();
			_this.ctx.arc(this.x + this.width / 2, _this.ch - 20 - _this.rand(0, 10), _this.rand(1, 8), 0, Math.PI * 2, false);
			_this.ctx.fill();
		};

		this.createParticles = function() {
			var i = this.particleRate;
			while(i--) {
				this.particles.push(new this.Particle());
			}
		};

		this.removeParticles = function() {
			var i = this.particleRate;
			while(i--) {
				var p = this.particles[i];
				if(p.y > _this.ch - 20 - p.height) {
					p.renderBubble();
					_this.particles.splice(i, 1);
				}
			}
		};

		this.updateParticles = function() {
			var i = this.particles.length;
			while(i--) {
				var p = this.particles[i];
				p.update(i);
			};
		};

		this.renderParticles = function() {
			var i = this.particles.length;
			while(i--) {
				var p = this.particles[i];
				p.render();
			};
		};

		this.clearCanvas = function() {
			this.ctx.globalCompositeOperation = 'destination-out';
			this.ctx.fillStyle = 'rgba(255,255,255,.06)';
			this.ctx.fillRect(0, 0, this.cw, this.ch);
			this.ctx.globalCompositeOperation = 'lighter';
		};

		this.loop = function() {
			var loopIt = function() {
				requestAnimationFrame(loopIt, _this.c);
				_this.clearCanvas();
				_this.createParticles();
				_this.updateParticles();
				_this.renderParticles();
				_this.removeParticles();
			};
			loopIt();
		};

	};

	var isCanvasSupported = function() {
		var elem = document.createElement('canvas');
		return !!(elem.getContext && elem.getContext('2d'));
	};

	var setupRAF = function() {
		var lastTime = 0;
		var vendors = ['ms', 'moz', 'webkit', 'o'];
		for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
			window.requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame'];
			window.cancelAnimationFrame = window[vendors[x] + 'CancelAnimationFrame'] || window[vendors[x] + 'CancelRequestAnimationFrame'];
		};

		if(!window.requestAnimationFrame) {
			window.requestAnimationFrame = function(callback, element) {
				var currTime = new Date().getTime();
				var timeToCall = Math.max(0, 16 - (currTime - lastTime));
				var id = window.setTimeout(function() {
					callback(currTime + timeToCall);
				}, timeToCall);
				lastTime = currTime + timeToCall;
				return id;
			};
		};

		if(!window.cancelAnimationFrame) {
			window.cancelAnimationFrame = function(id) {
				clearTimeout(id);
			};
		};
	};

	if(isCanvasSupported()) {
		var c = document.getElementById('waterfall');
		var cw = c.width = 100;
		var ch = c.height = 140;
		var waterfall = new waterfallCanvas(c, cw, ch);
		setupRAF();
		waterfall.init();
	}
</script>